In a conventional electrophotographic image forming device, an electrostatic latent image is formed on a photosensitive drum. Toner accommodated within a developing cartridge is supplied to the electrostatic latent image, thereby forming a toner image on the photosensitive drum. The toner image is then transferred onto a sheet to form an image on the sheet.
One of such conventional developing cartridges includes a casing, a toner accommodation chamber for storing toner therein, a developing roller rotatably supported to the casing, a thickness-regulating member for regulating a thickness of toner carried on the developing roller and sealing members for preventing toner from leaking outside. The thickness-regulating member includes a leaf spring whose one end is fixed to the casing and a thickness regulating portion fixed to the other end of the leaf spring. The sealing members are disposed on both widthwise ends of the developing roller and are attached to the leaf spring.
In the developing cartridge of the above configuration, the sealing members are carefully attached to the leaf spring for sealing a groove between each sealing member and the thickness regulating portion in order to prevent toner leakage. The sealing members are attached by a double-sided adhesive tape with extreme care.